Optimization of Extraction Process and In Vitro Antioxidant Activity of Polysaccharides from Fibrous Roots of Ophiopogon japonicus

Objective This study aims to optimize the ultrasonic circulation extraction process of polysaccharides from the fibrous roots of Ophiopogon japonicus (Zhejiang origin) and evaluate their in vitro antioxidant activity, so as to provide an experimental basis for the efficient extraction and subsequent development and utilization of these polysaccharides.

Method Plackett-Burman experimental design was adopted to screen factors affecting the extraction yield of polysaccharides from the fibrous roots of O. japonicus. Subsequently, response surface methodology was used to optimize the significant factors and determine the optimal extraction parameters and validate them; Finally, the in vitro antioxidant activity of the polysaccharides was evaluated using DPPH radical and superoxide anion scavenging assays.

Result Three core significant factors were screened out: extraction time, liquid-solid mass ratio and extraction times. The optimal extraction process was as follows: extraction frequency of 2 times, extraction time of 39 min, and material-liquid ratio of 87 g·ML^-1. Under these conditions, the extraction rate of polysaccharides was(39.89±0.23)%, which had no significant difference from the model predictions. At the concentration of 1 000 μg·mL^-1, O. japonicus polysaccharides showed higher scavenging rates for DPPH free radicals and superoxide anions.

Conclusion  Plackett-Burman experimental design combined with response surface methodology can effectively optimize the ultrasonic circulation extraction process of O. japonicus polysaccharides, with stable process and ideal extraction rate. The O. japonicus polysaccharides obtained have certain in vitro antioxidant activity and great potential for further development.